This section provides background information related to the present disclosure which is not necessarily prior art.
Fast neutron imaging is an active area of research as it offers unique imaging modalities compared with traditional x-ray and thermal neutron imaging, such as the ability to nondestructively discern features in low-Z objects shielded by thick high-Z materials. In digital fast neutron imaging for example, fast neutrons are passed through a target onto a scintillator whose light is collected by a CCD camera. Scintillator thicknesses of multiple centimeters are required to detect MeV level neutrons with viable efficiencies. Collimated neutron beams are thus typically used because uncollimated and divergent beams will induce a cone beam effect in the resulting image due to both the finite thickness of the target and the scintillator itself. However, collimating a neutron source through increased source distance-to-target drastically reduces the neutron flux incident on the target and results in significantly longer imaging times.